> Of course, what I'm saying is science fiction, we don't have self-driving cars capable of driving 30mph to pick us up.

I suppose you're being sarcastic ? We already do have such cars. http://en.wikipedia.org/wiki/Driverless_car It will not be long before they are provably safer than professional human drivers.

However, that doesn't get rid of all the problem : your car still have to drive in and out the city. But if you combine automation with sharing, then you can afford smaller, more specialised cars. You could have tiny delivery cars (they don't even need to transport a human). You could have truly individual commute cars that would take just 1 person. By using the car that fit the job and use less space, we may be able to help with congestion.

Example of a "commute car": http://en.wikipedia.org/wiki/File:EN-V_Pride_%28Jiao%29.jpg

I hope when those cars arrive, I won't have to own one. Instead I hope they'll just make cabs so cheap that I can always use them in cab mode.

Or just walk ten minutes to the underground location.

I would guess that the average person might cover .5 mile (< 1km) in 10 minutes so it wouldn't be possible to reach the parking that's located "many miles" away. Also, I didn't say your car is 10 minutes by foot away, more like 10 miles. It could easily be 15-20 minutes for your car. Your goal is to minimize your commute time not your cars.

This wouldn't work in NYC or London, which are much bigger cities than discussed in the article. The first leg of your journey there should be a train whisking you away from the city at 120 mph to a train station within 15-20 miles of your home where your car will leave home to pick you as soon as your phone tells it you are 15 minutes from your station.

That sounds very inefficient. Fill the roads with cars that don't even have drivers in them. The optimal solution it to just commute less.

Same number of cars as today. Granted, each car will be driving a little more but pickup and dropoffs could be made more efficient with taxi stand pull-up lanes, for example.

I think the commuting option doesn't seem to work for many people. Seems like people spend too much time on the lawn, but sure it does work for some people.